RHODIUM-103 NMR OF CARBOXYLATE AND THIOLATE COMPLEXES BY INDIRECT DETECTION USING PHOSPHORUS

Fifty four carboxylate and thiolate complexes of rhodium including [Rh (O(2)CR)(PPh(3))(3)] (R = CH3, CF3), [Rh-2(SC6F5),(PPh(3))(4)] and der ivatives obtained by reaction with hydrogen, pyridine and methyldiphen ylphosphine, [Rh(O2CArN)(H)(2)(PPh(3))(2)] (O2CArN = pyridine-2-carbox ylate and related chelating ligands) and complexes prepared in situ (m any as mixtures) by the reaction of [Rh(H)(PPh(3))(4)] with various th iols were studied by two-dimensional inverse (103)Rk-(31)p correlated NMR (HMQC). Rhodium chemical shifts were found to fall within the rang e 840 to - 422 ppm. Trends in delta(103)Rh for thiolate and carboxylat e complexes are similar but not identical, with somewhat lower delta f or most of the thiolates, increasing in the approximate order [Rh(SR)( H)(2)(PPh(3))(3)] < [Rh(SR)(PPh(3))(3)], cis-[Rh(SR)(PPh(3))(2)(py)] < [Rh-2(SR)(2)(PPh(3))(4)] <[Rh(SR)(H)(2)(PPh(3))(2)(py)] < [Rh(SR)(2)( H)(PPh(3))(2)(py)]. (C) 1997 by John Wiley & Sons, Ltd.